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Publication numberUSRE29388 E
Publication typeGrant
Application numberUS 05/759,237
Publication dateSep 6, 1977
Filing dateJan 13, 1977
Priority dateFeb 14, 1973
Publication number05759237, 759237, US RE29388 E, US RE29388E, US-E-RE29388, USRE29388 E, USRE29388E
InventorsAlan W. Atkinson
Original AssigneeTurner & Newall Limited
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Glass compositions and fibers made therefrom
US RE29388 E
Abstract
Glass compositions, having improved chemical resistance and useful in the form of fibers for reinforcing cementitious materials, consisting essentially of:
From 50 to 75 percent by weight Silica
From 10 to 25 percent by weight R2 O
from .[.1.]. .Iadd.7 .Iaddend.to 15 percent Titania
From 1 to 20 percent by weight Zirconia
From 0.8 to 20 percent by weight Rare Earth Oxide
From 0 to 20 percent by weight Boric Oxide
From 0 to 10 percent by weight R1 O
from 0 to 1 percent by weight Fluorine as (fluoride)
From 0 to 2 percent by weight Al2 O3
from 0 to 1 percent by weight P2 O5
from 0 to 1 percent by weight Chlorine (as chloride)
Where R2 O is sodium oxide, potassium oxide or a mixture of both, optionally including up to 5% by weight of lithium oxide (based on the total composition) and R1 O is MgO, CaO, BaO, or SrO, or a mixture of two or more thereof.
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Claims(21)
I claim:
1. A glass composition, having improved chemical resistance to alkali attack, consisting essentially of:
from 50 to 75 percent by weight Silica
from 10 to 25 percent by weight R2 O
from .[.1.]. .Iadd.7 .Iaddend.to 15 percent by weight Titania
from 1 to 20 percent by weight Zirconia
from 0.8 to 20 percent by weight Rare Earth Oxide
from 0 to 20 percent by weight Boric Oxide
from 0 to 10 percent by weight R1 O
from 0 to 1 percent by weight Fluorine (as fluoride)
from 0 to 2 percent by weight Al2 O3
from 0 to 1 percent by weight P2 O5
from 0 to 1 percent by weight Chlorine (as chloride)
wherein R2 O is selected from the group consisting of Na2 O, K2 O, mixtures thereof, and mixtures thereof containing up to 5% by weight lithium oxide (based on the total weight of the composition) and R1 O is selected from the group consisting of MgO, CaO, BaO, and SrO, and mixtures of two or more thereof.
2. A glass composition according to claim 1, including not more than 30%, by weight of the titania and zirconia together.
3. A glass composition according to claim 1, comprising at least 20% by weight of ZrO2 and TiO2 together.
4. A glass composition according to claim 1, comprising at least 23% by weight of ZrO2, TiO2 and rare earth oxide together.
5. A glass composition according to claim 1, including not more than 7% by weight of the R1 O.
6. A glass composition according to claim 1, wherein any of R1 O, fluorine Al2 O3, P2 O5 or chlorine's present in impurity amounts.
7. A glass composition according to claim 1, containing not more than 15% by weight of zirconia.
8. Glass fiber having a composition as defined in claim 1.
9. Cementitious material, including as reinforcement therein up to 30% by weight of glass fiber as defined in claim 6.
10. A glass composition consisting of:
______________________________________Silica               50% by weightSodium Oxide         10%Lithium Oxide         1%Boric Oxide           3%Titania              10%Zirconia             10%Cerium Oxide         15%Sodium Fluoride       1%______________________________________
11. A glass composition according to claim 10, in the form of fibers.
12. A glass composition consisting of:
______________________________________Silica               58% by weightSodium Oxide         13%Titania               9%Zirconia             12%Boric Oxide           3%Ceric Oxide           5%______________________________________
13. A glass composition according to claim 12, in the form of fibers.
14. A glass composition consisting of:
______________________________________Silica               56% by weightSodium Oxide         12%Titania               8%Zirconia             13%Boric Oxide           3%Calcium Oxide         6%Ceric Oxide           2%______________________________________
15. A glass composition according to claim 14, in the form of fibers.
16. A glass composition consisting essentially of:
______________________________________Silica               58% by weightSodium Oxide         14%Titania              10%Zirconia             13%Boric Oxide           4%Barium Oxide         0.1%Mixture of naturallyaccuring rareearth oxides         0.8%Cl                   0.1%______________________________________
17. A glass composition according to claim 16, in the form of fibers.
18. A glass composition consisting essentially of:
______________________________________Silica               58% by weightSodium Oxide         13%Titania               7%Zirconia             14%Boric Oxide          0.5%Calcium Oxide         4%Barium Oxide         0.6%Mixture of naturallyaccurring rare earthoxides               2.5%Cl                   0.4%______________________________________
19. A glass composition according to claim 18, in the form of fibres.
20. A glass composition, having improved chemical resistance to alkali attack, consisting essentially of:
______________________________________from 50-58    percent  by  weight                            Silica"    11-14    "        "   "     R2 O"     8-10    "        "   "     Titania"    10-14    "        "   "     Zirconia"    0.8-15   "        "   "     Rare Earth Oxide"    0.5-4    "        "   "     Boric Oxide"    0.1-6    "        "   "     R1 O"    0-1      "        "   "     Fluorine (as fluoride)"    0.1-0.4  "        "   "     Chlorine (as chloride)______________________________________
wherein .[.R20.]. .Iadd.R2 O .Iaddend.is elected from the group consisting of Na2 O, K2 O, mixtures of the two, and mixtures thereof additionally containing up to 1% by weight lithium oxide (based on the total weight of the composition) and R1 O is selected from the group consisting of MgO, CaO, BaO, SrO and mixtures of two or more thereof.
21. A glass composition according to claim 20, in the form of fibers.
Description

This application is a continuation-in-part of new earlier application Ser. No. 441,984 filed Feb. 13, 1974, now abandoned.

BACKGROUND OF THE INVENTION

This invention concerns improvements in or relating to glass compositions, fiber made therefrom and cementitious materials including such fiber as reinforcement.

Glass compositions, containing beryllia, magnesia, strontium oxide, titania, cadmium oxide or zirconia have been known for many years (see, for example, U.K. Patent Specification Nos. 595,498 and 791,374 and U.S. Pat. No. 2,640,784). From these, refractory glass fiber and other articles may be made.

More recently, U.S. Pat. No. 2,877,124 discloses compositions which are chemically durable, have a low liquidus temperature and slow devitrification and are capable of being formed into fibers by rotary spinning and attenuation of the strands so obtained. These compositions comprise, in weight percent;

______________________________________SiO2            50 to 65Al2 O3     0 to 8CaO                  3 to 4MgO                   0 to 10Na2 O, K2 O, L2 O                10 to 20B2 O3       5 to 15TiO2            0 to 8ZrO3            0 to 8BaO                  0 to 8Fe2 O3      0 to 12MnO                   0 to 12ZnO                  0 to 2______________________________________

And preferably are essentially free from at least a majority of the six last-named components.

U.S. Pat. No. 3,127,277 discloses glasses of high modulus of elasticity, of composition, in weight percent:

______________________________________SiO2         45-60CaO                9-19MgO                6-10BeO                7-12ZrO2         1-3Li2 O        up to 4TiO2          2-10CeO2         up to 4______________________________________

Optionally including other ingredients such as Fe2 O3 and Al2 O3.

U.S. Pat. No. 3,817,764 disloses glass compositions, in weight percent:

______________________________________SiO2         49-57Al2 O3  3-5B2 O3    6-12Na2 O        18-20CaO               0-2TiO2          9-12ZrO2         0-7Fe2 O3    0-0.5LiO2         0-1______________________________________

and states that glass fibers which are especially water durable, and can be made from these compositions by rotary or centrifugal spinning.

Finally, U.S. Pat. No. 3,861,925 discloses alkali resistant fiberizable glass compositions which are zirconia free and consist essentially of, in weight percent.

______________________________________SiO2            55-65TiO2, La2 O2 or CeO2,                12-25CaO                  4-6Na2 O,          12-18K2 O            0-3______________________________________

Despite such disclosures, however, there is still a need for glasses having improved chemical durability -- in particular improved resistance to alkali attack, for example for use in reinforcing cementitious articles.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, a glass composition consists essentially, by weight of the composition, of:

from 50 to 75% Silica

from 10 to 25% R2 O

from .[.1.]. .Iadd.7 .Iaddend.to 15% Titania

from 1 to 20% Zirconia

up to 20% Rare Earth Oxide

from 0 to 20% Boric Oxide

from 0 to 10% R1 O

from 0 to 1% Fluorine (as fluoride)

from 0 to 2% Al2 O3

where R2 O is sodium oxide, potassium oxide or a mixture of both, optionally including up to 5% by weight lithium oxide (based on the total composition), and R1 O is MgO, CaO, BaO or SrO, or a mixture of two or more thereof.

A preferred glass composition consists essentially, by weight of the compositions, of:

from 50 - 58% Silica

from 11 - - % R2 O

from 8 - 10% Titania

from 10 - 14% Zirconia

from 0.8 - 15% Rare Earth Oxide

from 0.5 - 4% Boric Oxide

from 0.1 - 6% R1 O

from 0 - 1% Fluorine (as fluoride)

from 0.1 - 0.4% Chlorine (as chloride)

Wherein R2 O is selected from the group consisting of Na2 O, K2 O and mixtures of the two and mixtures thereof additionally containing up to 1% by weight lithium oxide (based on the total weight of the composition) and R1 O is selected from the group consisting of MgO, CaO, BaO, SrO and mixtures of two or more thereof.

The compositions preferably comprise at least 20% by weight of ZrO.sub. 2 and TiO2 together, and at least 23% by weight of ZrO.sub. 2, TiO2 and rare earth oxide together.

The composition preferably contains not more than 30%, and more preferably not more than 25% by weight, of titania and zirconia together, and not more than 7% by weight of R1 O. The R1 O and F may be deliberately added to the composition, within the ranges of content stated above. If Li2 O is used in place of fluorine then comparable amounts of Al2 O3 will be added (necessarily but not desirably) by way of the raw materials commercially available at present. Al2 O3 should not exceed more than 2% by weight of the composition.

The inclusion of a rare earth (metal) oxide imparts to the glass compositions of this invention a degree of alkali resistance not, in general, exhibited by glass compositions of otherwise similar formulation. At least 0.8% rare earth oxide is present in the composition.

The rare earth oxide used may be any of the naturally occurring ones, preferably ceric oxide, or a mixture of naturally occurring rare earth oxides. The term "naturally occurring rare earth oxide mixture" is well recognised in the Art used in the following examples according to its accepted meaning denoting a mixture of rare earth metal compounds (mainly the oxides) in which such metals are present in relative abundancies approximately equivalent to their naturally occurring relative abundancies. Such mixtures are constituted by, for example, a natural rare earth ore such as bastnaesite or monoazite; the term is also used as herein to denote such an ore which has been treated to remove undesirable components such as carbonate, phosphate or fluoride ions. When bastnaesite, for example, is treated to remove such ions, the rare earth metal content remains constant, and remains proportional to the naturally occurring abundance.

The detrimental effect of excessive amounts of certain ions, such as phosphate or fluoride, in glass making is well known to those skilled in the art, so as suitable naturally occurring rare earth oxide mixture can be prepared by taking an ore such as bastnaesite or monazite and pre-treating it in an appropriate manner.

It is already well known that the chemical properties of rare earth metals and their oxides are markedly similar; I would expect that most, if not all, of the rare earth oxides -- and particularly any mixture thereof containing cerium -- give a result closely similar to the results obtained from compositions containing cerium oxide as the sole rare earth oxide.

The glass compositions of this invention consist essentially of the ingredients specified above, but may be found to include also a trace amount, i.e. up to about 1%, of phosphate and/or of chlorine present as the chloride.

Preferred embodiments of the invention, embodying the above principles, are illustrated in the following Examples 1 to 5; comparative results for a modified prior art composition are illustrated in Example A.

EXAMPLE 1

A glass of the following composition was prepared and was melt drawn at 1230 C:

______________________________________Silica               50% weightSodium Oxide         10%Lithium Oxide         1%Boric Oxide           3%Titania              10%Zirconia             10%Cerium Oxide         15%Sodium Fluoride       1%______________________________________

The glass fibers obtained exhibited a tensile strength of 1.36 GPa (Giga Pascals - equivalent to GN/m2).

Fibers of this composition were boiled in saturated Ca(OH)2 for 4 hours, washed successively with water, 1% hydrochloric acid (1 minute), water, and acetone, and then dried. The strength of the fiber was increased to 1.55 GPa.

EXAMPLES 2 TO 5

Glasses of various compositions as set forth in the following table were melt drawn, and the tensile strength thereof was determined before and after alkali treatment, with the results shown.

______________________________________Composition      Examples% by weight      2       3       4     5______________________________________SiO2        58      56      58    58Li2 O       --      --      --    --Na2 O       13      12      14    13TiO2         9       8      10     7ZrO2        12      13      13    14B2 O3   3       3       4    0.5CaO              --       6      --     4BaO              --      --      0.1   0.6CeO2         5       2      --    --Naturally occurringRare Earth Oxide mixture*            --      --      0.8   2.5F                --      --      --    --Cl               --      --      0.1   0.4Tensile Strength (GPa)before alkali treatment            1.22    1.04    1.07  1.25Tensile Strength (GPa)after alkali treatment            0.87    0.63    0.73  1.19______________________________________ *Obtained by treating a bastnaesite ore to remove carbonate and fluoride ions.

The alkali resistance of the above compositions make them eminently suitable for use as fibrous reinforcement in cementitious materials. They may be used in an amount up to 30% by weight of the total dry weight of cementitious materials, preferably in an amount of from 5 to 10% by weight.

COMPARATIVE EXAMPLE A

I. A composition was made as disclosed in Example 2 of U.S. Pat. No. 2,877,124 (which Example contains the maximum proportions of TiO2 and ZrO2 exemplified in this patent), and to this composition an addition of 4% by weight of CeO2 was made, 4% CeO2 being the maximum content of rare earth oxide mentioned in U.S. Pat. No. 3,127,277, to provide the following glass composition:

______________________________________SiO2          50.98 weight %B2 O3     6.04Al2 O3    2.38Fe2 O3    2.97MgO                 3.60CaO                 7.40BaO                 2.80Na2 O         12.90TiO2           2.97ZrO2           3.40CeO2           4.00______________________________________

At first instance it might appear that this modified composition should provide fibers of an alkali resistance equivalent to that obtained by use of the present invention. I have found, however, that such similar properties are not obtained as demonstrated below.

Fibers were made from this composition, and were tested for alkali resistance, by the methods described in the preceding Examples.

The following results were obtained:

Strength before alkali treatment 0.99 GPa

Strength after alkali treatment 0.64 GPa

II. A composition as in (I) above, but containing no rare earth oxide was formed into fibers, and these were tested, by the same methods, with the following results:

Stength before alkali treatment 1.24 GPa

Strength after alkali treatment 0.48 GPa

The fibers exemplified in Examples 1 to 5 have strengths after alkali treatment of from 1.04 to 1.55 GPa, which clearly shows that fibers produced from these compositions exhibit considerably greater strengths after alkali treatment than can fibers produced by the modification referred to above. That is, fibers made in accordance with this invention have greater alkali resistance.

III. As a further comparison, Example 2 was repeated using 4% ceric oxide; this gave fibers having a strength of 0.94 GPa before treatment with alkali, and 0.90 GPa after alkali treatment. Without any ceric oxide a similar composition gives a strength of 0.66 GPa before treatment and 0.57 after alkali treatment. Thus, the percentage decline in the strength of fibers made from Example 2 composition, with or without ceric oxide, is less than for an Example A (I) composition with ceric oxide.

Obviously, modifications may be made in the compositions of this invention as exemplified above. It should be noted, however, that certain compositions within the composition ranges of this invention may not necessarily exhibit an especially marked increase in alkali resistance over similar compositions not containing rare earth oxide, or may exhibit a tendency to devitrify during fibre drawing; accordingly, the considerations and adjustments already used in glass technology to account for these difficulties should be applied to the invention for such compositions, not exemplified above, as come within the scope of the invention.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2640784 *Jan 21, 1950Jun 2, 1953Owens Corning Fiberglass CorpComposition of glass, especially for fibers
US2877124 *Nov 25, 1955Mar 10, 1959Owens Corning Fiberglass CorpGlass composition
US3127277 *Nov 17, 1960Mar 31, 1964 Glass composition
US3523803 *Apr 27, 1965Aug 11, 1970Saint GobainManufacture of borosilicate glass fibers
US3736162 *Feb 10, 1972May 29, 1973Ceskoslovenska Akademie VedCements containing mineral fibers of high corrosion resistance
US3783092 *Mar 23, 1971Jan 1, 1974Nat Res DevCement compositions containing glass fibres
US3785836 *Apr 21, 1972Jan 15, 1974United Aircraft CorpHigh modulus invert analog glass compositions containing beryllia
US3817764 *Jun 27, 1972Jun 18, 1974Owens Corning Fiberglass CorpFiberizable fluorine-free glass compositions
US3861925 *Feb 12, 1973Jan 21, 1975Owens Corning Fiberglass CorpAlkali-resistant, zirconia-free, fiberizable glass compositions
US3861926 *Nov 10, 1972Jan 21, 1975Pilkington Brothers LtdGlass fiber compositions of R{HD 2{B O-ROZrO{HD 2{B SiO{HD 2{B
US3861927 *May 4, 1973Jan 21, 1975Kanebo LtdAlkali resistant glass fibers
GB791374A * Title not available
Non-Patent Citations
Reference
1 *"Refractory Glass Fibers", Gates, Jr. et al. Ceramic Bulletin, vol. 46, No. 2 (1967), pp. 202-205.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5382552 *Sep 14, 1993Jan 17, 1995Miles Inc.Rare earth-containing alkali silicate frits and their use for the preparation of porcelain enamel coatings with improved cleanability
EP0500325A1 *Feb 19, 1992Aug 26, 1992Nippon Electric Glass Company, LimitedChemically resistant glass fiber composition
Classifications
U.S. Classification501/38, 501/59, 106/711, 501/56, 501/64, 501/57, 501/58
International ClassificationC03C13/00, C03C3/112, C03C3/089, C03C3/04, C03C3/095
Cooperative ClassificationC03C3/089, C03C13/002, C03C3/04, C03C3/095, C03C3/112
European ClassificationC03C3/095, C03C13/00B2, C03C3/089, C03C3/04, C03C3/112